Circuit breaker



Nov. 29, 1938. R c, VAN s cK 2,138,391

CIRCUIT BREAKER Filed June 5, 1936 4 Sheets-Sheet l INVENTOR ioswe/lClbnfibk/e Nov. 29, 1938. R. c. VAN SICKLE 2,133,391

CIRCUIT BREAKER Filed June 5, 1956 4 Sheets-Sheet 2 WITNESSES:

J OR Z2 4 #05 We a Van Sick/e ATTORN NOV. 29, 1938. R c VAN SlcKLE 2438 3 91 CIRCUIT BREAKER Filed June 5, 1936 4 Sheets-Sheet 5 Nov. 29, 1938. R c, VAN s c 2,138,391

01301111 BREAKER Filed June 5, 1936 4 Sheets-Sheet 4 m WITNESSES: INVENTOR I W /?05we// C Van Sick/e WM 6? GW Q/W 50 arcs are drawn.

Patented Nov. 29, 1938 V UNITED STATES PATENT OFFICE CIRCUIT BREAKER of Pennsylvania Application June 5, 1936, Serial No. 83,600

20 Claims.

This invention relates to circuit breakers, and more particularly to are extinguishing devices therefor.

More specifically, the invention relates to improvements in an arc extinguishing structure of the type shown and described in the copendihg application of H. C. Lingal and R. C. Dickinson, Serial No. 743,697, filed September 12, 1934 now Patent No. 2,112,033 issued March 22, 1938 and assigned to the assignee of this application, in which structure an alternating current arc is drawn between a pair of separable contacts positioned in a generally annularly shaped passage defined by a stack of plates of insulating material.

The passage has considerable axial length and has an arc terminal at each end thereof to provide a path. for the ends of the are which is I adapted to be rotated around the passage by a magnetic field set up radially across the passage.

80 The are passage is substantially completely enclosed and adapted to be filled with oil or other suitable arc quenching liquid which is readily decomposed when acted upon by an arc to produce a gas which contains a high percentage of 25 relatively cool un-ioniz'ed particles. These gas particles are caused to fiow through and intermingle with the arc stream so that when it passes through the current zero sufficient deionization will take place to prevent the are 30 from restriking when the voltage builds up in the opposite direction.

Although one or two reignitions at the current zero is considered good high speed performance 1 for such structures, are extinguishment at the 35 first current zero is desirable and in fact ispossible of attainment. In the copending application of B. P. Baker and W. M. Leeds, Serial No.

82,408, filed May 29, 1936 and assigned to the assignee of this application, a high speed circuit 40 breaker is shown having two arc extinguishing assemblages each comprising a plurality of arc extinguishing units adapted for tandem operation. 1

The particular arc interrupting structure de- 45 scribed in the last named application provides for the production of ten arcs in series with five in each assemblage. The individual arc extinguishing units comprise a generally annularly shaped arc passage. in which the separate series related The Baker and Leeds application above referred to deals particularly with magnetic means for moving the arc from the main contacts onto the arcing contacts provided at the ends of the 66 respective arc passages. These magnetic means comprise two sets of coils for each arc extinguishing unit. The first are moving means comprises a single coil in series with the main and only are forming contacts which sets up a radial magnetic field .across the upper end of the arc 5 passage so as to move the upper end of the arc onto the upper arc horn of each unit.

The second are moving means'comprise a coil adjacent both the upper and lower end of the arc passage, which coils have a larger number of 10 turns and a much smaller thermal capacity than the first mentioned coil. The second coils are adapted to be inserted in the arc circuit upon the transfer of the upper end of the arc of each unit from one of the main contacts onto the are 15 horn. The second or smaller coils are so arranged and connected that upon the aforesaid transfer of the are that both of the coils will be energized so that they are jointly operative to produce a strong radial magnetic field. for completing the transfer of the arcv from the lower main contact onto the lower arc horn and also to rotate the are along the arc horns at a high velocity.

Inasmuch as the first coil is connected in series with the main current carrying contacts, it must of necessity have a high current carrying capacity and consequently is limited to a small number of turns. The magnetic effect of the 'coil is, therefore, limited in that the field produced is not of sufilcient magnitude to rotate the are at such velocities as are required for high speed are extinguishment. The requisite high strength magnetic field is thus provided by the second coil system which gives satisfactory operating results over a wide range of current values.

It has been discovered, however, that particularly on currents of extremely large magnitude that a coil arrangement of this type drives the arc at such a high velocity that it may under certain circumstances reach the end of the arc horns in the passage before it is effectively extinguished.

An improvement in arc extinguishment, particularly for such high current values, has been effected by the particular treatment of the side walls and general shape of the arc passage as more clearly shown and described in the copending application of H. M. Wilcox, Serial No. 83,597, filed concurrently herewith, now Patent No. 2,095,301 issued October'12, 1937 and also assigned to the assignee of this application. In this application, the arc passage has a general shape similar to that disclosed in the aforenamed Baker and Leeds application. However, certain of the plates providing oil pockets adjacent the arc passage have been constructed with barriers extending transversely of the passage so as to slow up the arc movement prior'to its reaching the end of its path of travel, as provided by the arc horns and the arc passage.

Inasmuch as the foregoing improvements deal with an arc extinguishing unit which is substantially enclosed and the extinguishment of an arc therein involves the production of gas by the decomposition of the arc quenching liquid in the passage, attention may advantageously be given to means for permitting the escape of gas thus produced. Each of the foregoing applications covering the several improvements named em body the venting means covered in a copending application of R. C. Dickinson and W. M. Leeds, Serial No. 82,594, filed May 29, 1936, and assigned to the assignee of this application.

Although the features briefly reierred to in the aforenamed copending applications when combined provide a highly eflicient high speed arc extinguishing structure capable of interrupting loads having a wide range of current magnitude, I have discovered that the operation of such structure may be improved in a number of instances.

It is a known fact that when an attempt is made to close the contacts of a circuit breaker under load, particularly a breaker of the oil type, an arc may be drawn before the contacts engage which vaporizes the oil between the contacts and builds up a pressure which opposes closing. The gas pressure may be high enough to place an additional load upon the levers of the closing mechanism sufiicientto cause a resulting deflection of the levers which may permit closing of the mechanism without closing the contacts.

It is, therefore, an object of my invention to provide a circuit breaker of the type above referred to, in which the reactive pressures tending to oppose closing of the contacts under load have been rendered ineffective.

A further object of my invention is to provide means in a circuit breaker oi the liquid immersed type in which the pressure created by an are established between the main contacts during the closing operation under load is utilized to assist in closing the contacts of the breaker.

I have also discovered that inasmuch as the arc passage within the arc extinguishing units of breakers of the type aforesaid are substantially completely enclosed, except for the venting means that the movement of at least one oi the main contacts into and out the arc passage during the opening operation produces a displacement of the oil from the passage. During the opening operation, the high speed withdrawal of the moving contact will leave a space within the passage which may be filled with gas without moving the surrounding oil or raising the gas pressure, thereby somewhat lowering the efliciency of operation of the arc extinguishing device.

A further object, therefore, of my invention is to provide means for avoiding the formation of pockets in the oil which may be produced by high speed movement of the movable contact out of the arc extinguishing passage.

A more specific object of my invention relates to utilizing the last named compensating means during the closing operation of the breaker to supplement the force exerted upon the moving contact by the actuating mechanism in an amount to compensate for the pressure created by the arc tending to oppose the closing of the main movable contact.

An ancillary object of my invention is to provide means within an arc extinguishing structure of the above-named type, in which the movement of the main contact into the arc passage causes the oil to be displaced to a cylindrical chamber provided with a piston operatively associated with the mechanism for moving the main contact member, so that during the opening operation the oil previously displaced during the closing operation will again be returned to the arc passage and fill the space left by the moving contact.

A still further object of the invention consists in means for directing a stream of oil or other are quenching liquid between the main contacts during the time of separation so as to assist the magnetic field coils in moving the are from the main contacts on to the are receiving horns. I

Other objects and advantages relate to details of the arc extinguishing structure and will be apparent from the following description taken i connection with the accompanying drawings, in which:

Figure l is a side elevation view of the circuit breaker of my invention showing the tank thereof partially in cross section,

Fig. 2 is a vertical sectional view taken through the upper portion of one of the arc extinguishing assemblages of the breaker of my invention, showing the uppermost end portion of the next adjacent arc extinguishing unit,

Fig. 3 is a vertical sectional view showing the lowermost arc extinguishing unit of one of the arc extinguishing assemblages of the breaker,

Fig. 4 is a cross sectional view taken along the line IVIV of Fig. 3, showing the slot-like arc extinguishing passage,

Fig. 5 is a fragmentary vertical sectional view of a modified form of construction of my invention, and

Fig, 6 is a cross sectional view taken along the line VI-VI of Fig. 5.

Referring to the drawings, the reference numeral l0 designates a tank or enclosure in which the arc extinguishing mechanism of my invention is housed. The upper wall of the tank I0 is provided with insulating bushings II and I 2 for conducting the line terminals i3 interiorly of the tank. To the lower end of each of the line terminals I8 is secured an arc extinguishing assemblage generally indicated at l5. Each arc extinguishing assemblage comprises a plurality of, in this instance five, arc extinguishing units H.

The electrical circuit through each are assemblage proceeds from the line terminal I3 through a series contact arrangement through each of the units ll which will be explained more fully hereinafter and terminates with a releas-. able contact member l9 positioned at the lower end of each of the arc extinguishing assemblages 15. The two releasable contact members I! are adapted to be interconnected by a bridging bar 2| which is movable into and out of engagement with the contact members I9 by a lift rod 23. The lift rod 23 is adapted to be actuated by a suitable mechanism not shown.

Each of the arc extinguishing units i1 is composed of a seriesof plates of insulating material arranged in contiguous relation to form a stack. This stack comprises plates of various construction indicated in the order from the top down as 25, 26, 21, 2B, 28, 30, 29, 28, 29, 20, 29, 28, 21,

26 and 25. All of the above designated plates with the exception of plates 25 have a curved tapering slot therethrough and the plates are so arranged that the slots are aligned to form an arc passage 3|.

The general outline of the arc passage 3| is defined by the thin plates 21 and 29. With particular reference to Fig. 4, the general arrangement of the arc passage 3| can be ascertained in that three of the plates 28, 29 and 39 are shown in superimposed relation. It will be noted that the plate 29 is provided with a wall defining slot 33. Immediately above plate 29 is plate 28, which generally also has a wall defining slot 35. However, the plate 28 is also provided with a plurality of indentures or recesses 31 adjacent each side of the slot 35. i

The plate 39 underlying the plate 29 is similar in construction to that of the plate 29 with the exception that the indentures 31 are shifted along the curved slot a distance equal to onehalf the width of the indenture. Thus, the passage 3| is provided with pockets formed by the indentures 31 which are arranged in staggered relation along the walls of the passage. Barriers 39 are positioned transversely of the passage 3| for a purpose which will be hereinafter'more fully described.

The upper and lower ends of the passage 3| are enclosed by the plates 25. The portions of the upper and lower plates 25 exposed to the passage 3| are adapted to support upper and lower arc horns designated at 4| and 43, respectively. The ends of the stack of insulating plates above described are provided withan upper end plate 45 and a lower end plate 41, each preferably of magnetic material. The end plates 45 and 41 are maintained in clamping engagement with the insulating plates 25 to 30 by means of tie rods 49 of insulating material passing through suitable apertures placed near the circumference of the aforesaid plates.

The units l1 are adapted to be maintained in spaced axial arrangement by means of a plurality of tie rods also passing through suitable apertures adjacent the circumferences of the units. The upper ends of the tie rods 5| are provided with a threaded portion 53 which may be bolted by means of a nut 54, to a contact foot 55 which, in turn, has threaded engagement with the lower end of the line terminal l3. The contact foot 55 provides for suspending the entire arc assemblage |5 from the lower end of the line terminal l3 and in addition provides means for conducting the current from the line terminal to the first or next adjacent arc extinguishing unit |1.

The particular connection will appear more fully in connection with a description of the circuit through the contacts of each arc extinguishing unit IT. The enlarged portion of the passage 3| is adapted to receive a pair of contacts 51 and 59. The contact 51 is fixed and is adapted to be supported from a series coil designated at 6|,

which, in turn, is embedded in an annular recess 63 provided in the upper magnetic end plate 45.

The lower, contact 59 is movable through a guide member 65 inserted through the lower insulating plate 25 and the lower magnetic plate 41.

The movable contact 59 is adapted to be coupled by means of a straight line linkage generally indicated at 61 to an operating rod 69 of insulating material which passes centrally-through each of the stacks of plates constituting theseparate units II. The straight line linkage mech- 'anism 61 comprises a lever 1| pivoted at one endpin 8| also has pivotal engagement with a stabilizing link 82 which is adapted to rotate about a fixed pivot 83 determined by a bracket 84 secured to the lower edge of the lower end plate '41. It will thus be seen as the operating rod 69 is reciprocated vertically, the movable contact 59 due to its connection through the actuating linkage 61 will be caused to move substantially parallel with the operating rod 59. In order to provide resilient contact pressure between the contacts 51 and 59, a pivotal pin 13 passing through the lower end of the contact 59 is adapt-' ed to bear against a spring 85 positioned in a suitable bore, as specifically shown in Fig. 3 within the contact 51. The limited amount of relative movement required between the pin 13 and the contact 59, is obtained by an elongated slot 86 in the contact 59.

It will be understood that each of the contacts 59 in the separate arc extinguishing units H are of identical construction and that each of the units |1 may be provided with identical straight line actuating mechanisms 61 which are'coupled by pins 8| to the operating rod 69 for simultaneous actuation thereby. Each of the fixed contacts 51 are provided with a cylindrical bore 9|, which bore is in registration with a similar bore -92 extending upwardly through the insulating end plate 25 and the metallic end plate 45.

The bore thus provided is lined with an insulating tube 93, the purpose of which will appear hereinafter. The tube 93 provides a cylinder which is co-axial with a guide member 94 secured to the upper metallic end plate 45, to constitute a cylindrical chamber 95. The chamber 95 is adapted to'receive a piston 95 secured to an extension 91 mounted on the lower end of the movable contact member 59. The lower end of the cylindrical chamber 95 has an outlet opening 98 provided through the side wall of the fixed contact 51.

It will thus be observed that if the movable contact 59 is moved from the open to the closed position, the piston 96 will be partially withdrawn from the cylindrical chamber 95 and thereby filling the chamber with are quenching liquid which is contained in the arc passage 3 Also when the movable contact 59 is moved from the closed to the open position, the piston 95 will expel the arc quenching liquid from the chamber 95 through the opening 98 into the arc passage 3|.

In order that the liquid ejected from the chamber 95 through the opening 95 may be directed between the contacts 51 and 59, I have provided a deflecting block 99 which may be positioned in suitable notches madein the first five upper plates 26 to 30. It will, of course, be observed that the fixed-contact 51 of the uppermost unit H has a construction similar tothe remaining fixed contacts in that it has been provided with a cylindrical chamber 95. This chamber does not receive a piston 95 in that there is'no movable contact 59 immediately above, whereby such piston would be actuated.

In order to create a flow of arc quenching liquid through the upper contact 51 of the uppermost unit, further provisions have been made which consist in providing a cylindrical chamber WI upon the upper magnetic end plate 45 of the uppermost unit I1. The cylindrical member "II is coaxial with respect to the operating rod 58 and is adapted to receive a piston I02 secured to the end of the operating rod. The area on the lower side of the piston between the rod 69 and the outer circumference of the piston I02 designated at I03 is effective in forcing oil from within the cylindrical member IOI through a passage 9 104 to the cylindrical chamber 95 of the upper contact 51. The upper end of the piston I02 is also provided with a guide pin I 05 extending through the upper end of the cylindrical member I 0| which also serves as a guide member for the operating rod 59.

In order to assist or to accelerate the opening movement of the operating rod 69, that is, a movement in a downward direction, the pair of accelerating springs designated I08 are provided 21 between the end of the cylindrical member IOI and the piston I02. The initial acceleration of the operating mechanism is supplemented by the springs 85 in each movable contact 59. The downward or opening movement of the operating rod 69 and consequently the movable contact 59 3Q lever H of the straight line linkage 61.

unit.

piston 96 attached by means of the extension 91 to the movable contact member 59 in the arrangement shown would serve no useful purpose in the lowermost unit I1, as shown in Fig. 3, such piston and extension may be omitted.

The magnetic are moving means whereby the arc is transferred from the contacts 51, 59 onto the upper and lower arc horns 4i and 43 are similar to that described in the aforementioned copending application of B. P. Baker and W. M. Leeds.

The coil SI which has been previously referred to is preferably one of high current carrying capacity having a few number of turns. One

.50 end of the coil 6|, as before mentioned, is connected to the upper contact 51, whereas the other end of the coil 6| has connection as by a screw M5 to the upper end plate 45. The annular recess 63 in the upper magnetic end plate .55 also contains a coil designated at H5. The coil H5 has a larger number of turns than the coil GI and has one end thereof connected, as shown in Figs. 2 and 3, by a dotted connection II 1 to the upper end plate 45. p

The other end of the coil H5 is connected, as shown by the dotted connection II8 to the arc horn 4|. The lower end plate 41 of each unit also has an annular recess II9 which is similar to the recess 63 in the upper end plate 45. The recess I I9 houses a coil I20 similar to the coil I I6 in the upper end plate 45. One end of the coil I20 is connected to the lower arc horn 43 which, in turn, is connected to the lower end plate 41.

The other end of the coil I20 is connected by .70, the conductor I23 to one end of the coil H5 in 75 As shown in Fig. 3, two series coils are employed in the lowermost unit I1. The upper coil 5|, as well as the upper coil H8, are similar in arrangement and connected as in the preceding units. The annular recess H9 in the lower end plate 41 of the lowermost unit in addition to housing the coil I20 also has a series coil I25 which is similar to the coil BI in the upper end plate 45, it differing from the coil GI only in its connections. Since the coil I25 is positioned in the lower end plate 41, means are provided as an aperture to allow the free passage of the movable electrode 59. One end of the coil I25 is connected by the lead I21 to the releasable contact I 9 which, in turn, is secured to the lower end of the operating rod 59.

The other end of the coil I25 is connected to the lower end plate 41. One end of the coil I20 is connected by a lead I29 to the lower arc horn 43. The other end of the coil I20 is connected to the end plate 41. In order to make electrical connection from the terminal I3 to the first are extinguishing unit I1, the connecting strip Ill is provided which bridges the contact foot and the upper end plate 45 of the uppermost unit. Succeeding units are adapted to be electrically connected by a bridging connector I33, respectively joining the lower end plate 41 of one unit with the adjacent upper end plate 45 of the next adjacent unit. The complete electrical circuit through each of the arc extinguishing assemblages I5 for the various positions of the electrode and arc with respect to the electrodes and the are receiving horns will now be considered.

When the electrodes are in the closed position, as shown in Figs. 2 and 3, the circuit from the incoming line terminal I3 proceeds to the contact foot 55, the bridging connection I3I to the upper magnetic end plate 45 through the connection II5 to the coil SI from the other end of the coil GI to the upper fixed contact 51. The movable contact 59 through a flexible shunt I35 connecting the movable contact 55 to the lower end plate 41 through a bracket I35 connected thereto. From the lower end plate 41, the circuit proceeds through the bridging connector I33 to the upper end plate 45 of the next lower unit through which, and also through'the succeeding .units, the circuit repeats itself until it reaches the lower end plate 41 of the lowermost unit.

From the lower end plate 41 of the lowermost unit I1, the circuit proceeds through the series coil I25 and from thence to the connection I21 to the releasable contact I9. It will, of course, be understood that the circuit through the other are extinguishing assemblage I5 is the same as that previously described, and that the connection between the two assemblages I5 is obtained by the bridging bar 2I making contact with the two releasable contacts I9.

From the foregoing circuit connection; it will be observed that the current flowing through the series coils GI will produce a radial magnetic field which is augmented by the upper magnetic end plate 45 and caused'to be directed radially across the upper end of the passage II. The action of the radial magnetic field thus produced in each of the units I1 will cause the upper end of anare drawn, as a result of the opening of contacts 51 and 59, to be moved onto the upper arc horn 4I.

As the upper arc horn 4| is engaged by the are, the electrical connection through the arc assemblage is as follows. The line terminal I2, contact foot 55, connection III, upper end plate 45, connection II1, coil II6, connection IIl,upper are horn 4i, movable contact member 59, flexible shunt I35, bracket I39, lower end plate 41, lower coil I20, connection I23, to the upper coil II9 of the next lower unit I1 from whence the circuit repeats for all succeeding units.

It will be observed that as soon as the upper end of the are produced between each of the contacts 51 and 59 shifts to the upper arc horn II the upper coil H9, as well as the lower coil I20 of each unit, will be inserted into the arc circuit since the lower coil I20 and the upper coil II9 of a next lower unit are connected in series. With the exception of the lowermost unit I1, the lower coil I20 is not as yet inserted into the arc circuit. The reason that it is not inserted in the circuit is that in all preceding units the lower coil I20 is connected in series with the upper coil I I6 of the next lower unit. Since there is no coil I I6 with which the lower coil I 20 of the lowermost unit I1 may be connected in series, the energization of such coil I20 must be deferred until complete transfer of the arc onto the lower horn 43. The advantage of having the lower coil I20 energized by the energization of the upper coil IIG of a next lower unit is that the joint action of the two coils is obtained more quickly than if the lower coil were inserted by the transfer of the arc to the lower horn which is in a less favorable position for'arc transfer.

It will be noted, however, that the lower end of the arc passage of the lowermost unit I1 is not without a magnetic field since there is provided a series coil I25 which is at all times in series with the arc circuit and hence provides the necessary field to initially move the are from the moving contact 59 onto the lower arc horn 93.

It will be noted that the series connection of the lower coil I20 of one unit with the upper coil II9 of the next adjacent unit I1 eliminates the necessity of providing a series coil similar to coil I25 in the lower end plates 41 of the four units I1 preceding the lowermost unit. The final circuit through the arc extinguishing assemblage I5,

that is, when the arc is completely transferred to the arc horns 4| and 93, is as follows. Terminal I3, contact foot 55, bridging connection I3I, the upper end plate 45, connection II1, coil II9, connection II9, arc horn II, are horn 93, coil I29, connection I23 and to the coil II9 of the next unit I1 from whence the circuit precedes through succeeding units until it reaches the lower arc horn 93 of the lowermost unit I1.

From this are horn the circuit proceeds through the coil I29 the coil I25, theconnection I21 which terminates at the releasable contact I9. In order I to maintain the magnetic characteristics of both end plates 45 and 41 the same, the annular recess 9 in the lower end plate 91 is constructed to the same dimensions as the upper annular recess 53. The space which would'ordinarily be occupied by a lower series coil I25 in the first four units of the arc extinguishing assemblage in the annular recess H9 is filled in with an annular plate of insulating material designated at I39.

The foregoing arrangement of coil connections for producing the radial magnetic field for are movement from the main contacts 51 and 59 onto the arc horns 9| and 93 is particularly adapted for the transfer of arcs of varying current magnitude. The continuous energization of the series coils 9| and I25 during the time that the contacts 51 and 59 are closed, supply a ready field so that as soon as these contacts open at leastthe upper end of the arc in all of the units I1 will be transferred onto the upper arc horn.

Although a comparatively low magnetic field is required for moving arcs of high current magnitude onto the arc horns, some difficulty may be experienced in obtaining movement of arcs onto the arc horns of arcs having extremely low current values. By arranging the fixed contacts 51 with a cylindrical'chamber 95 and providing pistons 96 made operative therein by the movement of an immediately adjacent movable contact 59,

then directing fluid contained in the cylindrical chamber 95 through the openings 99 during the opening movement of the contacts and directing the stream of liquid thus ejected by means of a deflecting member 99 between the fixed and moving contacts, are movement from these contacts onto the arc horns is rendered more positive.

The prime function, however, of the hollow fixed contacts 51 and the pistons 96 contained therein is to provide means for balancing the force exerted upon the movable-contacts due to pressure created within the passage 3| caused by an arc during the closing operation of the movable contacts 59 under load. From Figs. 2 and 3 it will be apparent that the pressure in passage 3i created by an arc during the closing operation of the movable contacts 59 will react through the passage 99 into the cylindrical chamber 95 and exert a force upon the lower surface of each piston 99.

Thus if the lower areas of each of the pistons 99 are equal to the upper contact area of the contacts 59, and since there are only four cylindrical chambers 95 with pistons 99 therein without further provision for balancing the pressure in the uppermost passage 3|, complete balance or the force at the contacts preventing closure would not be obtained. In order to obtain a complete balance of these forces, the pressure in the .the operating rod 99.

It will be apparent that by properly proportioning the area I09, the difference in the moment arm maybe accounted for so as to give the entire system of contacts absolute balance during the closing operation under conditions of load. However, in the'event that it would not be desirable to provide for balancing means exteriorly of the upper grid unit I1, the balance of the entire systemcould be obtained by changing the ratio of the areas of the pistons 99 with respect to the areas oi. the contacts 59. Since five arc extinguishing units I1 are shown, and assuming that the pressure in each of the passages 3| of each unit is the same, the ratio of area of the pistons 99 to the area of the contacts 59 would have have to be l where is the total number of arc extinguishing units. a

From the foregoing description, it will readily be seen that the hollow fixedcontact arrangement provided with a piston 99 also'avoids the formation of pockets or void spaces in the arc extinguishing liquid during the opening operation of the fixed contacts 59. As the movable contact 59 moves into the passage 3| and the piston 95 of the corresponding contact 51 moves upwardlmthe quantity of liquid displaced by the contact" will be caused to flow into the cylindricalchamberll.

During the opening operation, as the'movable contact 59 recedes from the passage 3|, the space formerly occupied by it will be filled with oil forced from the chamber 95, thereby tending to maintain the arc space between the contacts filled at the outset of the arc extinguishing operation. It will also be remembered that the expulsion of the oil from the chamber by the piston 95 assists in moving the arc from off the electrodes 51 and 59 onto the are horns 4| and 43.

The gas formed during arc extinguishment within the passage 3| is permitted to escape through suitable vent passages provided at the upper and lower ends of the passage adjacent the arc horns. The vent means, as shown more clearly in Fig. 3, and more fully shown and described in a copending application of R. C. Dickinson and W. M. Leeds, Serial No. 82,594, filed May 29, 1936, and assigned to the assignee of this application, comprises an annularly shaped chamber |4| substantially concentric with the passage 3| and positioned in the upper end of the upper plate 26 and the lower end of the lower plate 26, which chamber communicates with the passage 3| by means of ports I43. The chamber MI is connected with an opening I45 passing axially through the end plates 45 and 25 at the upper end of the unit, and also through the plates 41 and 25 at the lower end of the unit.

In Figs. 5 and 6, a modified arrangement is shown wherein compensation for the force exerted upon the movable contact may be had during the closing thereof under load. As illustrated in these figures, the arc passage 3| is enlarged in that it includes a cylindrical passage I5| adjacent the movable contact 59. The chamber I5| communicates with the passage 3| by a passage I52. A piston I53 is adapted to extend into the chamber |5| through an aperture I54 in the lower end plate 41. The piston I53 is coupled by a link I55 pivoted intermediate its end at I 56 to a bracket I51 secured to the lower end plate 41. A suitable operating mechanism similar to that shown at 61 in the previous figures, may also be employed to actuate the movable contact 59. It will be observed from these figures that any pressure created within the chamber 3| caused by an are due to the closure of the contacts 51 and 59 will react upon the piston I53 through the connecting link I55 and tend to assist the closing of the contact 59. By apportioning the area of the piston I53 and the contact 59 inversely with respect tothe moment arms about their pivotal connection I56, exact balance can be obtained.

It will also be observed that as the contact 53 moves into the passage 3| into contacting en- 'gagement with the fixed contact 51, the piston I53 will be withdrawn from the passage 3|, thereby preventing the liquid within the passage 3| from being forced therefrom. Also when the contact 59 is withdrawn from the passage, the plunger I53 will be forced farther into the passage, therefore, preventing the formation of pockets or void spaces in arc extinguishing liquid within the passage 3| between the electrodes.

The arrangement shown in Figs. 5 and 6 is also useful in providing the fiow of 011 between the contacts 51 and 53 as a result of the piston I53 during the opening operation in order to assist the magnetic field coils in moving the are from the contacts onto the arc horns.

It will be observed that the modifications shown in Figs. 5 and 6 may be particularly adapted to a circuit breaker embodying two. are extinguishing units singly. That is, a construction in which each line terminal I3 supports but one are extinguishing unit. It is also apparent that the construction of Figs. 5 and 6 when embodied in a multiple unit, as shown in the preceding figures, may be arranged for completely balanced conditions in each unit independently of the other units.

From the foregoing description, it will be apparent that I have provided a circuit breaker embodying a multiple break arc extinguishing structure in which provision has been made to compensate for the reactive forces exerted upon the moving contacts caused by pressure due to the formation of an arc during closure of the contacts under load which forces oppose the closing of the contacts. I have shown how such compensation may effectively be obtained for both multiple and single arc extinguishing unit structures. The foregoing also discloses wherein the compensating arrangement is made to function as a means to assist arc transfer from the main electrodes to suitable are receiving terminals. A further function of such arrangement is directed to the prevention of void spaces between the fixed and movable contacts upon the rapid separation of these contacts thereby increasing the arc extinguishing efficiency of the structure.

Although a number of specific arc extinguishing structures have been particularly described as for instance arc extinguishing units having annularly shaped arc passages therein, it is to be understood that the same is for purposes of illustration and that the pressure balancing arrangement herein disclosed may be used with equal effect in arc extinguishers of different form. I, therefore, do not wish to be limited by the foregoing as many changes and modifications may be made by those skilledin the art without departing from the spirit and scope of the appended claims.

I.claim .as my invention:

1. In a circuit breaker, an arc extinguishing device comprising means for defining an arc passage, an arc extinguishing liquid within said passage, a pair of contacts having .engageable contact surfaces within said passage, at least one of said contacts having a portion projecting exteriorly of said passage, means associated with said exteriorly projecting portion and moving the said one contact into and out of engagement with the other contact, a movable member having a portion within and a portion without said passage, and a linkage connecting said movable member with said movable contact arranged to operate the member in a direction opposite to the movement of said movable contact to compensate for the displacement of liquid within said passage caused by the movement of said movable contact.

2. In a circuit breaker, an arc extinguishing device comprising means for defining an arc chamber, an arc extinguishing liquid within said chamber, a pair of contacts having e'ngageable contact surfaces within said chamber, at least one of said contacts having a portion projecting exteriorly of said chamber, actuating means operatively connected to said contact portion exteriorly of said chamber for moving said one contact into and out of engagement with the other contact and means responsive to the pressure within said arc chamber produced by an are between the contacts during the closing operation thereof under conditions of load and operatively coupled to said actuating means for exerting a force on the latter which opposes the force exerted thereon by the pressure within said are chamber acting upon said movable contact.

3. In a circuit breaker, an arc extinguishing device comprising means for defining an arc passage, an arc extinguishing liquid within said passage which gives off a gas when acted upon by an are, a pair of, contacts having engageable contact surfaces within said passage, at least one of said contacts being movable into and out of engagement with the other of said contacts, said movable contact member being subjected to a force caused by the gas pressure produced by an are between the contacts during the operation thereof under conditions of load, said force acting in a direction to move said movable contact to the open position, a movable member within said passage also subjected to a force caused by said gas pressure, and means for operatively connecting said movable member with said movable contact, said connecting means being arranged to cause the force exerted upon said movable member to compensate the force exerted upon said movable contact.

4. In a circuit breaker, a plurality of are extinguishing units arranged end to end, each unit comprising means of insulating material for defining a substantially closed arc passage, arc quenching liquid in each of said passages, a pair of separable contacts in each passage, common actuating means for simultaneously actuating said pairs of contacts either to open or closed positions, and means associated with each unit operatively coupled to said actuating means and responsive to the pressure within each of said passages to balance the reactive forces resulting from the action of said pressure in each of said passages upon said contacts.

5. In a circuit breaker, a plurality of are extinguishing units arranged end to end, each unit comprising means of insulating material for defining a substantially closed arc passage, arc quenching liquid in each of said passages, which gives off a gas ,when acted upon by an are, a pair of contacts in each of said passages, common actuating means connecting one of said contacts of each pair in tandem for simultaneous operation of the contacts so connected to open and closed positions, said movable contacts being subjected to a force caused by the gas pressure produced within each passage by an are between the contacts during the closing operation thereof under load, said force opposing the force applied to said actuating means for closing said contacts, and means utilizing the pressure within each passage to exert a force upon said movable contacts in the direction of that applied by said actuatin means to ofiset the force tending to prevent contact closure.

6. In a circuit breaker, a plurality of are extinguishing units arranged end to end in spaced relation, each of said units comprising means of insulating material for defining a substantially enclosed arc passage, a fixed contact member in each of said passages, a movable contact member extending into each of said passages, said fixed and said movable contact members being arranged end' to end in axial alignment, one end of said movable contact member being adapted to make contacting engagement with its cooperating fixed contact member, the other end of each of said movable contact members serving as a piston, said fixed contact members having a cylindrical bore therein open at one end for operatively receiving the piston of a movable contact. member ,of a unit next adjacent, the otherend of the bore in:

responding fixed contacts.

7. In a circuit breaker, a plurality of are extinguishing units arranged end to end in spaced relation, each of said units comprising means of insulating material for defining a substantially enclosed arc passage, a fixed contact member in each of said passages, a movable contact member extending into each of said passages, said fixed and said movable contact members being arranged end to end in axial alignment, one end of said movable contact member being adapted to make contacting engagement with its cooperating fixed contact member, the other end of each of said movable contact members serving as a piston, said fixed contact members having a cylindrical bore therein open at one end for operatively receiving the piston of a movable contact member of a unit next adjacent, the other end of the bore in each of said fixed contacts having an opening leading into the arc passage of its respective unit, an arc quenching liquid within each of said passages, and actuating means for operatively connecting said movable contact members in tandem for simultaneously operating said members to open and closed positions to cause an alternate fiow of liquid between said passages and their corresponding fixed contacts, and means for directing the liquid displaced from said fixed contact members during the opening operation of said movable contact members between said fixed and movable contact members.

8. In a circuit breaker, an arc extinguishing assemblage comprising a plurality of are extinguishing units arranged end to end in spaced relation, each of said units comprising means of insulating material for defining the walls of a narrow arc passage, a fixed contact in the upper end of each unit, a movable cooperating contact for each unit movable through the lower ends of said units, said contacts being arranged end to end in axial alignment, actuating means coupling said movable contacts together for tandem operation, at least one of said fixed contacts of an intermediate unit having a cylindrical bore therein open at its outer end for operatively receiving a piston, said fixed contact having an opening adjacent its other end connecting the cylindrical bore and the arc passage, 2. liquid in said passage which gives off a gas when acted upon by an are to aid in extinguishing the are, said piston being k created within said passage caused by an are due to closing the contacts under load to produce a force to oppose the force produced by said pressure acting upon the movable contact.

'9. In a circuit breaker, means of insulating material defining the walls of a generally annularly shaped arc passage, a fixed and a movable contact member for drawing an arc longitudinally of said passage, means "for setting up a radial magnetic field for rotating said are around said passage, a liquid within said passage which gives off a gas when acted upon by an arc to aid in extinguishing the arc, and means operatively coupled to said movable contact utilizing the pressure created by an arc upon closing the electrodes under load for assisting the closing of said movable contact against said pressure, said last named means being operative during the opening operation said movable contact to cause a flow of liquid against the arc to assist said magnetic field in moving the arc.

10. In a circuit breaker, an arc extinguishing assemblage comprising a plurality of arc extinguishing units arranged end to end in spaced relation, each unit comprising means of insulating material for defining the walls of a generally annularly shaped arc passage, a liquid in each of said passages which gives off a gas when acted upon by adam to aid in extinguishing the arc, a hollow fixed contact in each unit having an opening leading from within the contact to said passage to conduct liquid from said passage to said contact. a piston operative in said hollow contact, a movable contact adapted for contacting engagement with said hollow contact for establishing an are within each of said passages, arc terminals within each passage for receiving the ends of the are established therein, means for setting up a radial magnetic field across each passage to rotate each arc therearound, actuating means coupling said movable contacts for tandem operation, means operatively coupling said pistons for simultaneous operation with said movable contacts, said pistons being adapted to squirt liquid between the fixed and movable contacts against the arcs during the opening operation of said movable contacts to assist in moving the arcs onto said are terminals, said pistons being adapted to utilize the pressure created by arcs within each passage upon closing the electrodes under load for assisting the closing of said movable contacts against the pressures created in each of said passages.

ll'. In a circuit breaker, means of insulating material defining the walls of a generally annularly shaped substantially enclosed arc chamber. a fixed and a movable contact member for drawing an arc longitudinally of said passage, means for setting up a radial magnetic field for rotating said are around said passage, a liquid with n said passage which gives oil a gas when acted upon by an arc to aid in extinguishing the arc, actuating means for operatingsaid movable contact to open and closed positions, a passage communicating with said are chamber, a piston in said passage operatively coupled to said actuat ng means and responsive to the pressure in the arc chamber to balance the reactive force resulting from the action of said pressure upon said movable contact, said piston being positively actuated by said actuating means during the opening movement of said movable contact to cause a fiow of liquid against the arc to assist the magnetic field in moving the arc.

12. In a circuit breaker, means of insulating material for defining the walls of a generally annularly shaped substantially enclosed arc passage, 8. liquid in said passage which gives ed a gas when acted upon by an arc to aid in extinguishing the arc, a hollow fixed contact within saidpassage having an opening communicating with said passage, a piston operating in said hollow contact, a movable contact adapted to cooperate with said fixed contact for wtablishing an arc within said passage, means for setting up a radial magnetic field across said passage for moving the arc therealong, a linkage for simultaneously actuating said piston and said movable contact, said piston causing a stream of arc-extinguishing liquid to be injected into said passage during the opening movement of said movable contact, and means for directing said stream of liquid between said contacts to aid the magnetic field in moving the are, said piston being operable through said linkage in response to pressure within said arc passage to balance the reactive force due to said pressure uponsaid movable contact.

13. In a circuit breaker, an arc-extinguishing unit comprising means of insulating material for defining a substantially enclosed arc passage, 2. fixed contact member in said passage, a movable contact member extending into said passage, said fixed and said movable contact members being arranged end to end in axial alignment, one end of said movable contact member being adapted to make'contacting engagement with a cooperating portion of said fixed contact member, said fixed contact member having a cylindrical bore therein open at one end, a piston operative in said bore, the other end of said bore having an opening leading into said passage, an arc-quenching liquid-within said passage and actuating means for operatively connecting said movable contact and said piston in tandem for operating said movable contact to open and closed positions and to simultaneously cause an alternate fiow of liquid between said passage and the bore of said fixed contact.

14. In a circuit breaker, an arc-extinguishing unit comprising means of insulating material for defining a substantially enclosed arc passage. a fixed contact member in said passage, a movable contact member extending into said passage, said fixed and said movable contact members being arranged end to end in axial alignment, one end of said movable contact member being adapted to make contacting engagement with a cooperating portion of said fixed contact member, said fixed contact member having a cylindrical bore therein open at one end, a piston operative in said bore, the other end of said bore having an opening leading into said passage, an arcquenching liquid within said passage and actuating means for operatively connecting said movable contact and said piston in tandem for operating said movable contact to open and closed positions and to simultaneously cause an al-- ternate fiow of liquid between said passage and the bore of said fixed contact, and means for directing the liquid displaced from said fixed contact member during the opening operation of said movable contact member between said contact members.

15. In a circuit breaker, an arc-extinguishing unit comprising means of insulating material for defining the walls of a narrow arc passage, 8. fixed contact in the upper end of said unit, a movable cooperating contact for said unit movable through the lower end thereof, said contacts being arranged end to end in axial alignment, actuating means for moving said movable contact to open and closed positions, said fixed eontact having a, cylindrical bore therein open at its outer end for operatively receiving a piston, said fixed contact having an opening adjacent its other end for connecting the cylindrical bore and the arc passage, 1!. liquid in said passage which givesofiagaswhenacteduponbyanarctoaid in extinguishing the arc, said piston being adapted to be actuated by said actuating means and simultaneously with said movable contact for drawing liquid from said passage into the fixed contact during the closing operation of the movable contact and for expelling the liquid from the fixed contact between the fixed and movable contacts, during the opening operation thereof, said piston being adapted to utilize the pressure created within said passage caused by an are due to closing the contacts under load to produce a force to oppose the force produced by said pressure acting upon the movable contact.

16. In a circuit breaker, an arc-extinguishing unit comprising means of insulating material for defining the walls of a generally annularly shaped arc passage, a liquid in said passage which gives off a gas when acted upon by an arc to aid in extinguishing the arc, a hollow fixed contact in said unit having an opening leading from within the contact to said passage to conduct liquid from the passage to within said contact, a piston operative in said hollow contact, a movable contact adapted for contacting engagement with said hollow contact for establishing an are within said passage, arc terminals within said passage for receiving the ends of the arc established therein, means for setting up a radial magnetic field across said passage to rotate the arc therearound, actuating means coupling said movable contact and said piston for simultaneous operation, said piston being adapted to squirt liquid between the fixed and movable contacts against the arc during the opening operation of said movable contact to assist in moving the arc onto said arc terminals, said piston being adapted to utilize the pressure created by an are within said passage upon closing the contacts under load for assisting the closing movement of said movable contact against the pressure created in said arc passage.

17. In a circuit breaker, means of insulating material defining the walls of a generally annularly shaped arc passage, a pair of separable contacts for drawing an arc longitudinally of said passage, actuating means for at least one of said contacts, means for setting up a radial magnetic field for rotating said arc around said passage, a liquid within said passage which gives off a gas when acted upon by an arc to aid in extinguishing the arc, and means actuated by'said actuating means for moving an additional quantity of liquid between said contacts to assist said mag- 'material defining the walls of a generally annularly shaped arc passage, an arc horn of generally annular shape disposed at each end of said arc passage, a pair of separable contacts for establishing an arc longitudinally of said passage, actuating means for at least one of said contacts, means for setting up a radial magnetic field for moving said are laterally along said passage between said arc horns, a liquid within said passage which gives off a gas when acted upon by an arc to aid in extinguishing the arc, and means actuated by said contact actuating means during the opening movement of said contacts for producing a fiow of liquid against the arc to assist said magnetic field in moving the are from between said contacts onto said arc horns.

19. In a circuit breaker, means of insulating material defining the walls of a generally annularly shaped arc passage, a pair of separable contacts for drawing an arc longitudinally of said passage, at least one of said contacts being movable axially through one wall of said are passage, actuating means for said one contact, means for setting up a radial magnetic field for rotating said are around said passage, a liquid within said passage which gives oil? a gas when acted upon by an arc to aid in extinguishing the arc, means actuated by said contact actuating means during the opening movement of said contacts for injecting an additional quantity of liquid into said passage to restrict the gas pocket between said contacts, and vent means disposed along said passage for the escape of gas therefrom, the initial gas flow through said vent means and said liquid flow assisting said magnetic field to move the are along said passage.

20. In a circuit breaker, a plurality of are extinguishing units, each unit comprising means of insulating material for defining a substantially closed arc passage, arc quenching liquid in each of said passages, a pair of separable contacts in each passage, common actuating means for simultaneously actuating said pairs of contacts either to open or closed positions and means associated with at least one of said units operatively coupled to said actuating means and responsive to the pressure within the arc passage of said one unit to counteract the reactive forces resulting from action of the pressure within each of said passages upon said contacts.

ROSWELL C. VAN SICKLE. 

